1. Field of the Invention
The present invention relates to a casting mold for producing a fiber-reinforced composite article by a die-casting process, i.e., a mold used for a die casting process to produce a fiber-reinforced composite article comprised of a formed product of fiber and a metal matrix.
2. Description of the Prior Art
In a die casting process, the gate speed of molten metal flow is on the order of about 30 to 45 m/sec and hence, the molten metal flow is brought into a turbulent flow within the cavity of the mold. If such a molten metal flow collides against a formed product of fiber, there is a possibility that the formed product of fiber may be deformed or broken, and there is also a possibility that the filling of the molten metal into the formed product of fiber may be impeded by air included into the molten metal flow. In a member including a simple-metal portion integral with the fiber-reinforced article, the air included in the molten metal flow forms air bubbles in the outer surface of the formed product of fiber due to the filtering effect of the fiber formed-product which permits the passing of only the molten metal, and as a result, blow holes are produced in the simple-metal portion.
Accordingly, it is now conventional practice to carry out the casting at a low gate speed of molten metal flow, reduced, for example, to about 0.4 m/sec.
With the conventional process, however, an existing injection device cannot be used, and an exclusive injection device is required, resulting in the problem that the equipment cost is increased, and the efficiency of production of the fiber-reinforced composite article is degraded with the reduction in gate speed of the molten metal flow.